🔍 Key Concepts

• Use the Stability Data Reference Book – SS AMERICAN MARINER, Sheet 2 to get displacement, TPI (tons per inch immersion), and the trim correction factors at the ship’s initial mean draft. • Treat each load/discharge as a separate trimming moment about amidships/LCF, using: tons × distance (forward = one sign, aft = the opposite sign). • Separate the effect of change of mean draft (net weight on/off) from the change of trim (longitudinal moments), then combine them to get final forward and aft drafts.

💭 Think About

• What is the ship’s initial mean draft and corresponding displacement/TPI from Sheet 2 before cargo work starts? • After you compute the algebraic sum of tons and of tons×distance, how do you convert the total trimming moment into inches of trim using the data on Sheet 2? • Once you know the total change in mean draft and total trim in inches, how do you split that trim between the forward and aft drafts based on the position of LCF relative to amidships?

✅ Before You Answer

• Make sure you keep a consistent sign convention: choose forward moments as plus and aft as minus (or vice versa) and stick with it for all four cargo operations. • Verify that you used the correct hydrostatic values at the initial mean draft (not at the final draft) from Sheet 2 – especially TPI and the trim factor/MT1". • After finding tentative final drafts, check that the change in displacement matches the net cargo loaded/discharged and that the sense of trim (by the head or by the stern) agrees with the net trimming moment.